1 files changed, 212 insertions, 0 deletions

diff --git a/net/ax25/ax25_ds_subr.c b/net/ax25/ax25_ds_subr.c
new file mode 100644
index 000000000000..10ffd2beba3f
--- /dev/null
+++ b/net/ax25/ax25_ds_subr.c
@@ -0,0 +1,212 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
+ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/spinlock.h>
+#include <linux/net.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+void ax25_ds_nr_error_recovery(ax25_cb *ax25)
+{
+        ax25_ds_establish_data_link(ax25);
+}
+
+/*
+ *      dl1bke 960114: transmit I frames on DAMA poll
+ */
+void ax25_ds_enquiry_response(ax25_cb *ax25)
+{
+        ax25_cb *ax25o;
+        struct hlist_node *node;
+
+        /* Please note that neither DK4EG´s nor DG2FEF´s
+         * DAMA spec mention the following behaviour as seen
+         * with TheFirmware:
+         *
+         *      DB0ACH->DL1BKE <RR C P R0> [DAMA]
+         *      DL1BKE->DB0ACH <I NR=0 NS=0>
+         *      DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+         *      DL1BKE->DB0ACH <RR R F R0>
+         *
+         * The Flexnet DAMA Master implementation apparently
+         * insists on the "proper" AX.25 behaviour:
+         *
+         *      DB0ACH->DL1BKE <RR C P R0> [DAMA]
+         *      DL1BKE->DB0ACH <RR R F R0>
+         *      DL1BKE->DB0ACH <I NR=0 NS=0>
+         *      DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5>
+         *
+         * Flexnet refuses to send us *any* I frame if we send
+         * a REJ in case AX25_COND_REJECT is set. It is superfluous in
+         * this mode anyway (a RR or RNR invokes the retransmission).
+         * Is this a Flexnet bug?
+         */
+
+        ax25_std_enquiry_response(ax25);
+
+        if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) {
+                ax25_requeue_frames(ax25);
+                ax25_kick(ax25);
+        }
+
+        if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL)
+                ax25_ds_t1_timeout(ax25);
+        else
+                ax25->n2count = 0;
+
+        ax25_start_t3timer(ax25);
+        ax25_ds_set_timer(ax25->ax25_dev);
+
+        spin_lock_bh(&ax25_list_lock);
+        ax25_for_each(ax25o, node, &ax25_list) {
+                if (ax25o == ax25)
+                        continue;
+
+                if (ax25o->ax25_dev != ax25->ax25_dev)
+                        continue;
+
+                if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) {
+                        ax25_ds_t1_timeout(ax25o);
+                        continue;
+                }
+
+                if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) {
+                        ax25_requeue_frames(ax25o);
+                        ax25_kick(ax25o);
+                }
+
+                if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL)
+                        ax25_ds_t1_timeout(ax25o);
+
+                /* do not start T3 for listening sockets (tnx DD8NE) */
+
+                if (ax25o->state != AX25_STATE_0)
+                        ax25_start_t3timer(ax25o);
+        }
+        spin_unlock_bh(&ax25_list_lock);
+}
+
+void ax25_ds_establish_data_link(ax25_cb *ax25)
+{
+        ax25->condition &= AX25_COND_DAMA_MODE;
+        ax25->n2count    = 0;
+        ax25_calculate_t1(ax25);
+        ax25_start_t1timer(ax25);
+        ax25_stop_t2timer(ax25);
+        ax25_start_t3timer(ax25);
+}
+
+/*
+ *      :::FIXME:::
+ *      This is a kludge. Not all drivers recognize kiss commands.
+ *      We need a driver level  request to switch duplex mode, that does
+ *      either SCC changing, PI config or KISS as required. Currently
+ *      this request isn't reliable.
+ */
+static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param)
+{
+        struct sk_buff *skb;
+        unsigned char *p;
+
+        if (ax25_dev->dev == NULL)
+                return;
+
+        if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL)
+                return;
+
+        skb->nh.raw = skb->data;
+        p = skb_put(skb, 2);
+
+        *p++ = cmd;
+        *p++ = param;
+
+        skb->dev      = ax25_dev->dev;
+        skb->protocol = htons(ETH_P_AX25);
+
+        dev_queue_xmit(skb);
+}
+
+/*
+ *      A nasty problem arises if we count the number of DAMA connections
+ *      wrong, especially when connections on the device already existed
+ *      and our network node (or the sysop) decides to turn on DAMA Master
+ *      mode. We thus flag the 'real' slave connections with
+ *      ax25->dama_slave=1 and look on every disconnect if still slave
+ *      connections exist.
+ */
+static int ax25_check_dama_slave(ax25_dev *ax25_dev)
+{
+        ax25_cb *ax25;
+        int res = 0;
+        struct hlist_node *node;
+
+        spin_lock_bh(&ax25_list_lock);
+        ax25_for_each(ax25, node, &ax25_list)
+                if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) {
+                        res = 1;
+                        break;
+                }
+        spin_unlock_bh(&ax25_list_lock);
+
+        return res;
+}
+
+static void ax25_dev_dama_on(ax25_dev *ax25_dev)
+{
+        if (ax25_dev == NULL)
+                return;
+
+        if (ax25_dev->dama.slave == 0)
+                ax25_kiss_cmd(ax25_dev, 5, 1);
+
+        ax25_dev->dama.slave = 1;
+        ax25_ds_set_timer(ax25_dev);
+}
+
+void ax25_dev_dama_off(ax25_dev *ax25_dev)
+{
+        if (ax25_dev == NULL)
+                return;
+
+        if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) {
+                ax25_kiss_cmd(ax25_dev, 5, 0);
+                ax25_dev->dama.slave = 0;
+                ax25_ds_del_timer(ax25_dev);
+        }
+}
+
+void ax25_dama_on(ax25_cb *ax25)
+{
+        ax25_dev_dama_on(ax25->ax25_dev);
+        ax25->condition |= AX25_COND_DAMA_MODE;
+}
+
+void ax25_dama_off(ax25_cb *ax25)
+{
+        ax25->condition &= ~AX25_COND_DAMA_MODE;
+        ax25_dev_dama_off(ax25->ax25_dev);
+}
+